| In the past few decades,the quantity of motor vehicles and energy consumption have an escalating increase by reasons of the rapid development of economy and industrialism and urbanization in China.At the same time,the air pollution is becoming more and more serious in China.Large-scale haze events occurred frequently in the north of China and the economically developed eastern coastal areas.The atmospheric environmental problems have been received extensive attention of the whole society.As one of the important pollutants leaded to haze episodes,atmospheric aerosols have raised widely focus in domestic and abroad because of its affects on atmospheric radiation,climate change and human health.In this study,the pollution current situation of atmospheric aerosol,the major emission sources of pollutants and the health risk of PM2.5 in China were analyzed and discussed from three aspects including fog water chemistry,fine particulate matter and atmospheric carbon aerosol pollution.In the study of fog chemistry.observation experiments were carried out along the middle and lower reaches of the Yangtze.The chemical characteristics of fog water and the major emission sources of pollutants were analyzed and discussed.The pollution current situation and characteristics of atmospheric aerosol along the middle and lower reaches of the Yangtze were summarized.The three-stage Caltech Active Strand Cloud water Collector(CASCC)was mounted on the board of a moving ship.Some important parameters including pH,electrical conductivity(EC).H2O2,HCHO,S(Ⅳ),ten inorganic ions(Na+,NH4-,K+,Mg2-,Ca2+,F-,Cl-,NO2-,SO42-,NO3-),seven organic acids(formate,acetate,propionate,butyrate,mesylate,oxalate,lactate)and sixteen trace metal elements(Al,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,As,Se,Sr,Cd.Ba,Tl,Pb)were measured.The pH values of the three-stage fog water samples ranged from weakly acidic(pH 4.3)to neutral(pH 7.05).And the electrical conductivity ranged from 32.37 to 436.3 μS cm-1 in this campaign.The concentrations of inorganic ions showed an obvious variation along the Yangtze River.which was likely due to the influence of anthropic factors.The main cations in fog water samples were NH4-and Ca2-,accounting for 12.35%and 29.07%of those inorganic ions,respectively.The major anions were SO42-and NO3-,accounting for 25.52%and 12.93%,respectively.And the dominant organic acid were formate and oxalate,accounting for 45.28%and 28.03%of the organic acids,respectively.Al,Fe,Zn and Ba dominated the detected trace metal elements in fog samples,accounting for 34.6%,16.4%.19.3%and 20.9%of those trace elements,respectively.Pollutants were expected to be mainly from human activities including fossil fuel combustion,biomass burning,steel-making,quarrying stone,and the emissions of human daily life.In addition,non-human factors including the natural background levels and long-range transport of sea salt particles also contributed to the pollution levels in fog events along the Yangtze River.In the study of fine particulate matter,the chemical characteristics,pollution sources and health risk of fine particulate matter in Beijing were analyzed and discussed.The pollution current situation and emission sources of atmospheric aerosol in north China are analyzed and summarized.The fine particles were collected per 8 hours during the winter in 2016 at southwest suburb in Beijing.Chemical compositions,including water soluble ions,organic carbon(OC),and elemental carbon(EC),as well as secondary organic carbon(SOC),were systematically analyzed and estimated.The total water soluble ions(TWSI),OC,and SOC of PM2.5 were with the following order:16:00-24:00>08:00-16:00>00:00-08:00.Since primary OC and EC were mainly attributed to the residential combustion in the night time,their valley values were observed in the daytime(08:00-16:00).However,the highest ratio value of SOC./OC was observed in the daytime,which was attributed to that SOC was easily formed under sunshine and proper temperature condition in the daytime.Positive matrix factorization(PMF),trajectory cluster of long-range transport,and potential source contribution function(PSCF)were employed for apportioning sources contributions and speculating potential sources spatial distributions.Six likely sources,including secondary inorganic aerosols,coal combustion,industrial and traffic emissions,road dust.soil and construction dust.and biomass burning,were estimated to account for 29%,21%,17%,16%,9%,and 8%,respectively,to PM2.5.Several seriously polluted areas that might affect the air quality of Beijing by means of long-range transport were identified.According to the results of PSCF analysis.Western Shandong.Southern Hebei,Northern Henan.Western Inner Mongolia,Northern Shaanxi,and the whole Shanxi provinces should be the key areas of air pollution control in China to improve air quality in north China.The exposure-response function was used to estimate the health and economic effects associated with PM2.5 pollution.The population affected by PM2.5 during haze episodes in winter at Beijing reached 0.31 million,the premature death cases associated with PM2.5 reached 2032.accounting for 1.4%of the total dead population in Beijing.Among the premature death cases,Lung cancer was the leading cause of premature death,accounting for 58.1%.In terms of economic effect,the total economic loss reached 967.6 million USD.accounting for 2.5 ‰ of the GDP in Beijing in 2016.Among the health endpoints,the major factor of economic loss was Lung cancer death which reached 366.0 million USD.followed by Chronic bronchitis,Respiratory disease death,Acute bronchitis and Cardiovascular disease deaths.In the study of atmospheric carbon aerosol,the chemical composition of atmospheric carbon aerosols,and spatial distribution of potential emission sources and health risk were analyzed and estimated.As one of the most populous and economically developed cities in the east of China,Jinan is facing a severe environmental challenge.To some extent,the pollution characteristics of atmospheric carbon aerosol in Jinan can represent the pollution status of atmospheric aerosol in the eastern coastal areas of China.The result showed that the mean concentration of PM2.5 was 88 ± 52 μg m-3 in Jinan during the period of observation.This level of PM2 5 was two times higher than the national ambient air quality standards(NAAQS,35 μg m-3).The mean concentrations of POC,SOC,and EC in PM2.5 were 5.45,2.59,2.76 μg m-3,respectively.The mean concentrations of POC and EC in haze days was 1.86 times higher than that in clear days.This result suggested that the pollution level of atmospheric carbon aerosol played an important role to the formation of haze events.Whether it is in haze days or clear days,the concentrations of SOC haven’t significant difference.The contribution rate of SOC to OC was about 32.4 ± 9.6%during the period of observation.In addition.the result showed that the contribution rate of atmospheric carbon aerosol to PM2.5 in clear days was higher than that in haze days.It might be attributed to that the contribution rate of SOC to PM2.5 in clear days was higher than that in haze days.The linear relationship of OC and EC during haze and clear days were also analyzed in this study.The result showed that OC and EC had a strong correlation(R2=0.7856)during haze days.This result suggested that OC and EC had similar emission sources and long-distance transport during haze days.However.OC and EC had a weak correlation(R2=0.4786)during clear days.This result should be attributed to that the contribution rate of SOC to PM2.5 during clear days was higher than that in haze days.Trajectory cluster of long-range transport and potential source contribution function(PSCF)were employed for apportioning sources contributions and speculating potential sources spatial distributions.Several seriously polluted areas that might affect the air quality of Jinan by means of long-range transport were identified.According to the results of PSCF analysis,the potential regional emission sources were mainly distributed in Shandong province.and the north of Zhejiang and Anhui province.At last,the health risk and economic effects associated with PM2.5 pollution in Jinan during observation were assessed.The cases of illness or death affected by PM2.5 pollution in Jinan reached 65.6 thousands.accounting for 0.91%of the total population in Jinan in 2016.The premature death cases associated with PM2.5 reached 666,accounting for 1.47%of the total dead population in Jinan in 2016.The total economic loss associated with PM2.5 pollution reached 202 million USD.accounting for 2.05 ‰ of the GDP in Jinan in 2016.Among the health endpoints,the major economic loss was from Lung cancer death which reached 48 million USD,followed by Respiratory disease death,Chronic bronchitis.Cardiovascular disease deaths and Acute bronchitis.These results provided important implication for making environmental policies to improve air quality in China. |
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